Device for the rapid detection of changes in the magnetic field of an electromagnet


The patent describes a device for a very rapid, sensitive and reliable detection of changes in the field strength of an electromagnet with low costs and high immunity to interference radiation.

Fields of Application

  • Emergency shut-downs of plants whose safety depends on magnetic fields (e.g. accelerators)
  • Estimation of the stability of magnetic fields in physical facilities or experimental setups
  • Surveillance or fine-tuning of magnetic power supplies
  • Surveillance of kicker magnets


A sudden unintentional change in a magnetic field can threaten people or systems in certain plants. For this reason, this magnetic field is being monitored and once rapid changes take place, the plant is being shut down.
The magnetic fields of electromagnets are generally measured either indirectly by current measurement through DCCTs (DC Current Transformers) or directly by Hall probes. The signals of these components for detection of changes can be evaluated in principle. However, the interference fields, which are usual in the field of high voltage components, may lead to false alarms in a hypersensitively adjusted minimum triggering level.


The developed method enables a very rapid and sensitive detection of magnetic field changes while maintaining very good immunity to interference by evaluating the voltage at the terminals of the electromagnet in a novel way. As a result, both an increase in sensitivity and a reduction of interferences and thus, a massive overall improvement in the signal-to-noise-ratio can be achieved in the relevant frequency range.


  • Faster response time, higher sensitivity, lower noise and lower interference sensitivity compared to Hall probes and DCCTs
  • Lower expenses by comparison

Development status

The principle has successfully been tested and several devices are already used by customers throughout Europe to their full satisfaction.